1. Field of the Invention
This invention generally relates to wireless communication systems and more particularly to wireless systems for transmitting data to mobile receivers.
2. Description of the Related Art
Communication systems such as wireless systems are designed to meet various demands of subscribers. Service providers continuously seek ways to improve the overall performance of the communication system. As wireless communications become more and more popular for subscribers to obtain data (i.e., email or information from the internet), communication systems must be capable of a higher throughput.
Proposed arrangements include scheduling the subscribers or users of the system according to the user's channel conditions. For example, a user is scheduled optimally when the user's channel is at a peak. When there are multiple data users within a cell, the transmission to a particular user may be delayed until the corresponding channel conditions improve. By switching between the various users depending upon their respective channel conditions, it becomes possible to schedule multiple users to receive information at different times. The nature of packet data transmission and reception allows for longer delays between transmissions compared to voice users.
One difficulty is presented when one or more subscribers in an area are stationary or moving relatively slowly. In this case their channel conditions may be adverse for extended periods of time. Even if these users are scheduled for transmission during those times, they will not be receiving data at the optimum rate, thereby diminishing the over-all system throughput.
This invention increases the throughput of a wireless data communication system especially when there are subscribers within an area that are stationary or moving slowly.